Aerial ladder



Jan. 26, 1954 H. J. TRocHE ET A1. 2,667,296

AERIAL LADDER Filed Feb. 18, 1950 5 Sheets-Sheet l HERMA/v J' Tfw CHEBYru-s Ha wana Ho/.AN

Jan- 26, 1954 H. J. TRocHE ET AL 2,667,296

AERIAL LADDER Filed Feb. 18, 1950 5 Sheets-Sheet 2 A; l p l' @i V NTORJ.l #fR/14N f, Roc/v5 f lm l JZMES Howlin@ HaLA/v BY )Lw fromm Jan. 26,1954 H. J. TROCHE ET AL 2,667,296

AERIAL LADDER Filed Feb. 18, 195o 5 sheets-sheet s A7701? EY Jarf- 26,1954 H. J. TRocHE ET AL 2,667,296

l AERIAL LADDER Filed Feb. 18, 1950 5 Sheets-Sheet 4 INVENTORJ. HERMA/vJ TocHE Z4/751s Hawano flo/.AN

Jan. 26, 1954 H. J. TRocHE Erm. 2,667,296

AERIAL LADDER Filed Feb. 1s, 195o 5 sheets-sheet 5 INI/ENTOR. Har/MN J.'TnocHE 3 Jil/wes Ho wana Hua/v Patented Jan. 26, 1954 Howard Holan,Rocky River, Ohio, assignors to J. H. Holan Corporation, Cleveland,Ohio, a.

corporation of' Ohio Application February 18, 1950, Serial No. 145,056

2 Claims.

The invention relates to aerial ladders, and particularly to aerialextension ladders adapted to be. mounted onutility truck bodies andutilized in the installation and maintenance of utility line equipment.The improved aerial ladder when not in use or when being transported isalso bedded on the truck body in closed condition.

The objects of the invention are to provide an aerial ladder of thecharacter stated which is of lightweight and may readily and easily beremoved from its bed, shifted into different positions and extended,collapsed and restored to its bed, all by one operator; which isstorable in or on the truck body for transporting without the loss ofstorage and crew space; which has a wide range of operating positions;and which provides a high factor of safety for the workmen.

The annexed drawings and the following description set forth in detailcertain means illustrating the improvements in aerial ladders, suchmeans constituting, however, only one of Vthe various forms in which theprinciple of the invention may be embodied.

In said annexed drawings:

Figure 1 is a side elevation of the aerial ladder, with the partsthereof extended to substantially its full working position, theposition of the ladder being that in which it has been tilted down fromits bed, extended, and is in a position where it can be turned aboutinto diiferent angular positions relative to the truck body upon whichit is mounted, the position shown in Figure 1 being that in which theextended ladder can be utilized longitudinally of the truck body; a partof the truck body being also shown in the ligure; also, there is shownin dot-and-dash lines a nested transporting position of the ladder uponthe roof of the truck body, the two parts of the ladder being in closedcondition; v

Figure 2 is a side elevation of an extreme outboard working position ofthe ladder, a position in which the ladder has been turned substantially90 from the position thereof shown in Figure l and moved outboard at thetop, certain other outboard positions through which the ladder moves inreaching the full line position shown in Figure 2 being indicated bydot-and-dash lines, the lefthand dot-and-dash position shown being aturning ladder position, diifering by 90 from the turning position shownin Figure l, this left-hand dot-and-dash position shown in Figure 2being one in which the ladder can be utilized in a substantiallyvertical position but pointed outboard of the truck body, or being onewhich is preparatory to the further desired exact positioning of theladder outboard of the truck body, the extreme outboard positioningbeing indicated, as stated, by the full line showing of Figure 2;

Figure 3 is a diagrammatic View illustrating a rope and pulley structurefor raising and lowering the upper ladder part;

Figure 4 is a side elevation, upon an enlarged scale, of alocking-assembly for securing the ladder upon the floor of the truckbody, a non-locking position of an operating lever and some Yrelatedelements being shown in dot-and-dash lines, this mechanism beingutilized for locking the ladder for operation thereof substantiallyvertically, either longitudinally or pointed outboard of the truck body,although when the ladder is used longitudinally of the truck body orpointed outboard and used substantially vertically of the truck body, itis not necessary to use this locking assembly, as will be hereinafteryfully described, this locking assembly in these uses being utilized, ifdesired, as an added safety feature;

Figure 5 is a front elevation of the elements shown in Figure 4, takenin the plane indicated by the line 5 5, Figure 4;

Figure 6A is a vertical transverse section, upon an enlarged scale,taken in a plane substantially at right angles lto the plane of theladder, this gure plane being indicated by the line 6 6, Fgure 5;

Figure 7 is a fragmentary plan'section of a ladder stile and rung andaclamping mechanism detail, upon an enlarged scale, taken at right anglesto the plane of the ladder and in thev plane l indicated by the line 11, Figure 5;

Figure 8 is a broken plan view, upon an enlarged scale, of a pivot platesecured to the floor of the truck bodyand of a base pivotally-mountedadjacent one of its ends on a side wall of the truck body and adapted tobe swung from an idle position adjacent the wa-ll of the truck body downto a working position where it rests upon the oor of the truck body, asshown in Figure 9, the iree or swinging end of the base in-its lowerposition extending substantially to the longitudinal center line of thetruck body, the base being shown in this Figure 8 in a lower laddersupporting position on the floor of the truckY body, and the view beingtaken `from the plane indicated by the line 8 8, Figure 2, this viewalso indicating in broken lines a bottom end ladder channel extendedbetween the side rails or Stiles of a lower ladder section, and alsochannel brackets exteriorly of the rails of the lower ladder section,through which channel brackets the ladder-lockine' bolts extend;

Figure 9 is a fragmentary vertical section, taken transversely of thetruck body and from the plane indicated by the line 9 9, Figure 8, andon the lower part of Fig. 8;

Figure 10 is a fragmentary vertical section, taken longitudinally of thetruck body and in the plane indicated by the line Iii-Ill, Figure 9;

Figure 11 is an elevation, upon an enlarged scale, taken substantiallyat right angles to the plane of the ladder, of one of a pair of certainautomatic vclamps mounted on the stiles of the lower ladder part forlocking the ladder to certain relatively right-angular pivot tubesmounted upon the truck body, respectively adjacent one side of the truckbody, and transversely of the truck body, and adjacent the top of thelatter, this view being an illustrative one in which the will behereinafter fully described. `When the clamp is shown as being locked tothe pivot tube extended longitudinally "of the truck body and thus theVladder is in position for use outboard of the truck body; and f Figure12 is a broken section, partially in plan,

taken in a plane at right angles to the plane of the ladder andindicated by the line I2-I2, Figure 11.

It will rst be stated that aerial ladders of the character hereinpresented are so designed and mounted that they may be utilized forservicing operations directly above the truck body or outboard thereofto the road curb and beyond. When working directly overhead, the truckbody can be operated so that one overhead position ofthe ladder servesthe purpose. However, when working outboard, there must be considerablelatitude to the reach of the ladder in order to provide for allreasonable uses thereof and, furthermore, the curb side of the street isoften blocked by parked vehicles and other obstructions so that theladder must be utilized over such obstructions from a position in thestreet inwardly of the curb. Y

Referring to the annexed drawings in which the same parts are indicatedby the saine respective numbers in the several views, a sloped skeletonframe 2 movable transversely of the truck body, Figure 2, is pivotallymounted adjacent one edge on and adjacent the bottom of the inside faceof a side wall of a truck body I, within the truck body, Figures 2, 8and 9. The opposed longitudinally-spaced sides of the frame 2 are shownin Figure 8, and from Figure 9 it will be noted-that the lower ends 59of these sides are wrapped about and secured to a shaft 3S pivotallymounted in brackets 48 secured to and adjacent Ythe bottom of theright-hand truck body side wall. Upon this skeleton frame 2 and itsassociated elements, when the frame is pulled down to ladder-receivingposition upon the floor I1 of the truck body I in the manner hereinafterfully described, and as shown in Figures 8, 9, and 10, is mounted theimproved aerial extension ladder for outboard use. The ladder has astationary lower section 3 with rungs I9 and an upper slidable orextensible section d.,Y having wood rungs 2l and the rails I5 of whichare slidable upon the rungs I9 of the lower section 3 for extending andclosing the ladder. As stated, the skeleton frame 2 is utilized forsupporting the ladder in its various outboard operating positions, theladder in such positions bearing against and being clamped to alongitudinal pivot tube mounted, as hereinafter fully described, uponthe roof of the truck body, the clamping of the ladder to the pivot tube6 being such as to permit swinging of the ladder over said pivot tube.'is

Yladder is utilized longitudinally of the truck body I, itis clamped toa cross-Wise pivot tube 5 for swinging movementthereover, this pivottube 5 being mounted upon and above the roof of the truck body I.

The mounting for the cross-wise pivot tube 5 and the longitudinal pivottube E comprises braced brackets 66 erected on the roof of the truckbody I adjacent its sides to which the pivot tubes 5 and 6 are securedby plates tid welded to the pivot tubes 5 and 6 and to the bracedbrackets 66.

When the ladder is manipulated or utilized substantially vertically,either pointed longitudinally of the truck body I or pointed outboard ofthe truck body I, it is mounted upon a pivot plate 2d, Figure 8, andsecured to the floor I1 of the truck body I by a pivot pin 25 passedthrough a central socket 26 of the pivot plate 2d, and registeringsockets in the bottom ladder channel 9 and in the truck body floor I1,or is secured by locking bolts passed through transversely alignedsockets 35 or longitudinally aligned sockets 29 of the pivot plate 2dand registering sockets in the truck body floor I1, all as hereinafterfully described.

The axes of the cross-wise pivot tube 5 and the longitudinal pivot tube6 lie in the same horizontal plane. These pivot tubes are provided withrespective disks 33 between which the ladder is swivelly clamped to thepivot tubes.

The improved ladder may be mounted upon and used with either a truckbody having a roof, or one without a roof, but is described'herein andshown in the accompanying drawings as utilized with a body having asliding roof.

In transporting position the upper ladder part 4 rests upon the lowerladder part 3 and the shortened ladder assembly is carried above` theroof of the body I upon the cross-wise tube 5, Figure l, which tube 5forms a support for one end of the closed ladder assembly, an oppositeend ladder support 58 being provided which is erected upon the truckbody I and has a ladder hold down part.

When it is desired to utilize the ladder, the hold down support 68 isunfastened and the closed ladder sections rocked over the tube 5 bypulling on the rear end of the lower ladder part 3 until the ladderassembly is in about a vertical position which aligns a central socket91 of the bottom ladder channel 9, secured between the side rails I4 ofthe lower ladder section 3, and which in this position of the ladderextends crosswise of the truck body I, Figure l, with a central socket25, Figures 1 and 8, formed through the pivot plate 24, there also beinga socket 63 through the truck body floor I1 registering with the pivotplate socket 26. A removable taperedend pivot pin 25, Figure l, isdropped through the registering sockets and thus the closed ladderassembly is pivotally mounted upon the floor I1 of the truck body I andbears against the cross-wise pivot tube 5 to which it is Ypivotallylocked as hereinafter fully described. The procedure Ljust described isa preparatory one if it is desired to use-theA ladder-outboard of thetruck body l.

However, if it is desired to the ladder with its plane cross-wise of thetruck body l, the pivot pin 255 may be inserted through the mentionedregistering sockets, as described, or the ladder can be secured byengaging manually-movable depending locking bolts t2, Figures- 4 and 5,mounted exteriorly of theside rails i iat the lower end of the laddervsection 3, with and looking them in opposed transversely-spaced sockets35 formed through and 'adjacent the opposite Iongitudinally-extendingsides of the pivot plate 2d, Figure 8, and registering withtransversely-op'- posed sockets 63 formed in the bodyl floor il. If

it is desired to use the pivot pin and the pivot plate socket 2S and thesockets registering therewith, the locking bolts 'i2 andthetransverselyspaced sockets and the floor sockets registering therewithmay be utilized as an added safety feature. The axes of the sockets 26and 35i of the pivot plate 2d are in alignment transversely Assuming,however, that the desired position Y of the ladder is for its use inoutboard operation, other than for use in a substantially verticalposition but pointed outboard such as is shown by the left-handdot-and-dash position of the ladder in Figure 2, it is turned angularlyabout upon 7 the pivot pin 25, from the position shown in Figure l tothe left-hand dot-and-dash position shown in Figure 2. lf it is desiredto use the ladder in the left-hand dot-and-dash position shown in Figure2, the pivot pin 25 can be utilised to secure it. If additional securityis desired, the locking bolts l2 can be engaged with longitudinallyopposed sockets 2Q, Figure 8, of thepivot plate 2d, and registeringlongitudinally-spaced iloor sockets 53, which sockets 29 are inalignment with the central pivot plate socket 25 and are angularly 96removed from the aforementioned transversely-aligned pivot plate socketsSe. However, if it is desired to use the ladder in a substantiallyinclined position, the pivot pin 25 f,

is removed, and the ladder moved bodily inwardly of the truck body i atthe bottoni, and' the locking bolts l2 are engaged with a selectedlongitudinally-aligned pair of two series of transverse sockets 23formed through inclined support plates 2l mounted on the inner or freeends of the respective arms of the skeleton frame 2, all as hereinafterfully described. There are a plurality of pairs of thelongitudinaily-aligned sockets 23 and the adjacent pairs aretransversely spaced and transversely-aligned. These pairs of sockets 2tare also transversely-aligned with the longitudinally-aligned sockets2%' of the .pivot plate 2d.

As stated, the pivot pin 25 is a removable member and it is utilized inthe socket 2B only for angular'rotating of the ladder and also forsubstantially vertical operation oi the ladder. When the ladder is to beutilized, it is locked yby the bolts 42 to the floor l1 through thesockets 29, or through the sockets t5, or locked in anylongitudinally-aligned pair of the transverse series of sockets 2Sformed in longitudinally-opposed inclined upper-flanged support stripsv2l mounted on the longitudinally opposed arms of the atore' series ofsockets 2.8? in the inclined. support strips lf'any one of the pairs oflongitudinally'- aligned sockets 28 below the upper sockets 28, FigureI9, are utilized, the outboard position of the ladder would notibe asextreme as theposition-'tlf'iereoi` shown in Figure 2, that pair oisockets 28 being utilized with Vthe locking bolts d'2 which willproduce-'the desired .inclined or outboard position `of the ladder.within the range provided by the plurality of. pairs or sockets Z3.

w When not in use, the vpivot pin is temporarily stored in anyconvenient location such as on a pin v5!! mounted inthe side wall oi thetruck body-i.

For the purpose of providing adequate depth of socket for the pivot pin2.5 a substantial block t2 Figures 8 and 9, is welded to the bottom faceof the truck body floor I1, this block 62 having a socket` registeringwith the pivot plate socket 26 and any other vertically-aligned sockets.

After the closed ladder has been rocked down to aposition. adjacent theii'oor i1 of. the truck body, and pivotally secured in the socket 2t, orlocked through the sockets 35 or swiveled for lateral positioning and/or locking inthe sockets 29, or pulled outwardly at the bottom forlocking in a pair of the inclined series of sockets 28, it is ek-``tended to the amount desired by pulling the upper ladder part 4 upoverthe lower ladder part 3, this action consisting in. sliding the siderails i5 of the upper ladder part 4 over the rangsr i9 of` the Ylowerladder part '3. Substantially the makiinum amount of extensionis shownin Figures l and 2, this `extension being lto an extent in which thelower support bars 34 of the bridge of the strut bars 23 `of the upperladder part 4 are about the heightof the upper rung l-fl l of the lowerladder part 3', providing an overlapping ladder part area indicated by15, Figures land'z. This extension of the ladder Vis effected by pullingon a cordv "l, Figure 3, which tracks over a swivel pulley '8 mounted-on the bottom channel member 9 of lthe lower ladder section 3, thencetracks over a swivel pulley l0 depending from the top rung i i of thelowerlad'cler' section 3, thence tracks over a swivel pulley IZ mountedon the bottoni rung' i3 of the upper ladder section 4, and thence 'isvsecured to the upper'lrung .irl of the lower ladder rsec-- tion 3.'I'he two ladder sections are of such tranwerse dimensions that thispulling upon the cord 'l causes the side rails i5 of the upper laddersection 4 to travel upwardly upon the rungs i9 of the lower laddersection 3. In the accompany-ing drawings the side rails i5 of the upperladder section 4 are shown as traveling on end wear collars '28 of thelower section rungs i9, Figure 5.

Describing now in detail the structure and operation of the severalelements and assemblies by which the vaforedescribed manipulation anduse ofthe ladder 'are effected.

The structure and actuation -o the pivoted skeleton frame 2 are asfollows. As stated, this frame 12 is fastened to the inside face of theY right-'hand side Aof the body i, when not in use,

.removing a lock pinand chain assembly there- 8, 9, and l0, welded attheir bottom edges to the two sides of the skeleton frame 2 and securedat their lower ends to collars 32 secured to the shaft 3Q, against whichcollars 32 the end mountings 48 of the shaft 3S abut. The supports 2l'are each providedwiththe series of four transversely-spaced sockets 28therethrough transversely-aligned with the sockets 29 of the pivot plate24 and adapted to receive the hinged locking bolts 42 depending. fromthe links 4t of two locking mechanisms, Figures 4 and 5. These lockingmechanisms depend from and exteriorly of the side rails Id of the laddersection 3, Figures 4 and 5. The plurality of pairs oflongitudinally-aligned sockets 28, and the inclination of the inclinedsupport plates 2l through which they are formed, provide means wherebythe ladder can be positioned and locked laterally outboard at differentinclinations therefor, the estreme position of which is shown by thefull line ladder position ofFigure 2.

The means for actuating the locking bolts 42 are shown in Figures 4 to7, inclusive. A hand lever 3b is pivotally secured at one end to a shell38 which is mounted in the ladder rails I4 and forms the bottom rung ofthe lower ladder section 3 in combination with stub end shafts 37.Pivoted at one end to the lever 36 intermediate the ends of the latteris a link 40 pivoted at its opposite end which is offset, Figures 4 and5, to one end of a locking bolt 42. The locking bolt 42 passes throughthe upper and lower anges of a channel bracket comprising an anglemember 43 and an angle member 431 which are secured together and alsobolted to and eXteriorly of a brace 49 for the ladder rail I4. Adjacentthe bottom of the bolt 42, and encircling it, within the bracket I3-431,is a collar 45 which is adapted to impinge upon an adjacently lowerblock 451 secured to the inside face of the bracket member 431. Mountedbetween the inside face of the bracket member 43 and the top face of thecollar 45 is a compression spring 44 secured at its bottom end to thecollar 45.

There is one of the locking mechanisms just described mounted upon eachside rail I4 of the lower ladder part 3 except that the lockingmechanism on the right-hand rail I4 is not provided with a hand lever36. In lieu of this hand lever 36, the right-hand locking mechanism isprovided with a short link 39, Figure 5, pivotally secured to the shell38 at one end and pivoted to the link 46 at its opposite end.

The locking mechanisms upon the two sides of the ladder are securedtogether by a channel bar 46, Figure 7, whose respective legs aresecured to the two ends of the shell 38 adjacently exteriorly of theladder rails I4.

The locking bolts 42, when in ladder-locking position, pass through thesockets 35, Figure 8, of the pivot plate 24 and also through alignedholes in the iioor I1 of the truck body I, when V the ladder isused'longitudinally of the truck body I, and pass through selectivepairs of sockets 28 in the support strips 2l, when the ladder is usedoutboard of the truck body I, and also pass through the sockets 29 ofthe pivot plate 24 and aligned holes in the floor I1 of the truck bodyI, when the ladder is used in a substantially vertical position, but ispointed outboard of the truck Vbody I, as shown by the left-handdotand-dash position thereof in Figure 2.

It is evident from an inspection of .Figure 4 y that pulling downwardlyupon the hand lever 36 will cause the upper end of link bar 4B to swingoutwardly and downwardly from the dotand-dash non-locking positionthereof shown and permit the springs 44 to effect the downward movementof the locking bolt 42 whereby the locking bolt 42 will be caused topass through the sockets 29 or 35 of the pivot plate 24, and theregistering sockets in the iloor- I1 ofthe truck body I, or through apair of the longitudinally-aligned holes 2B of the support strips 2l,all depending upon the position of the ladder and the directionin whichit is pointing and, in the event the ladder is resting upon the pivotbar 6 and is outboard, depending upon the inclination of the ladder.

When it is desired to release the locking bolts 42, the hand lever 35 ispushed toward the dotand-dash position thereof shown in Figure 4,whereby the bolts 42 are lifted into ladder-unlocking positions and thelinks 41% pass the projections of the axes of the bolts 42.

U-straps 41 secured to the links 40 intersect the locking paths ofmovement of the hand lever 35 and the short link 35 whereby the extentof the locking movement of the bolts 42 is' limited.

As above stated, the ladder is normally swingingly clamped to the crosstube 5 and this tube 5 serves to hold and support the bottom end of theladder in transporting position and provides an overbalancing mediumover which to rock the ladder down preparatory to use thereof as well asproviding a clamping medium for the ladder for use thereoflongitudinally of the truck body I. For use of the ladder pointedoutboard of the truck body I, or used outboard of the truck body I, thelongitudinal pivot tube is the one to which the ladder is pivotallyclamped for swinging movement of the ladder. The normal position of theclamping means is the locked position which is assumed automaticallyupon contact of the clamping means with the pivot bar 5 or the pivot bar8. These clamping means, and the elements for unclamping them, are shownin detail in Figures ll and l2. Assuming that it is desired to use theladder outboard, or pointed outboard, pivot tube Si would be the oneutilized and, for illustrative purposes, this is the condition shown inFigures ll and 12. Adjacently inwardly of the longitudinal pivot tubeand parallel therewith is mounted in the side rails I4 of the lowerladder section 3 a shell Se through which extends a shaft 5I to whoseprojecting ends hubs 5l are pinned. A release lever 55 is pinned to theleft-hand hub 5l. The hubs ii? are disposed slightly inwardly of thelateral ladderaligning disks 33 which overlap the hubs 5l. Formedintegrally with the inner ends of the hubs 5l are coupling elementspivotally mounted on the shaft -5I and having each a jaw 53 and a tailpiece 54. Abutting the outer side face of the rail I4 is a support barI3 for the strut rod 22 of the lower ladder section 3, through which barI8 the shaft 5I and shell 56 pass, as also a coll spring 58 one end ofwhich is secured in the rail I4 and the other end of which is secured inan enlarged end portion 541 of the hub 51 with which the couplingelement is integrally forned. The inner edges of the support portions I8overlap the rails I4 of the lower ladder section 3. The tendency of thespring 58 is to turn the hub 51 and the release lever 55 andconsequently the coupling member so as to cause the jaw 53 of the latterto clamp down over the pivot bar 6 as shown in Figure 1l. 'I'he outerend of the strut support member I8 has an arcuate portion |81 adapted toengage the pivot tube 5 and thence is of sub-divided nature so as toprovide upper and lower pads which have inwardly converging guidesurfaces 6D and 681 which, as the clamping member, upon the movement ofthe ladder, approaches the pivot bar 5 pass over the upper and lowersurfaces of the pivot bar and thus perform a guiding functio There isthe same clamping mechanism adjacent each rail I4 of the lower laddersection 3 except that the release lever55 is provided on the left sideonly.

As stated, the coupling member is normally in locked position forswiveling of the ladder over a pivot tube. This ladder locking isautomatically effected as follows. As the rails i4 carry thepivotally-mounted coupling members having the jaws 53 approach the pivottube, the upper part of a downwardly sloping face portion 531 of the jaw53 encounters the pivot tube S and, upon further approach f the railsI4, the sloping portion 531 of the jaw 53 causes the coupling member toswing on the shaft I, against the tendency of the spring 58, wherebyeventually the nose 532 of the jaw 53 clears the pivot tube 6 and thespring 58 then snaps the jaw 53 into the clamping position on the pivottube 5 shown in Figure 11. The clamping movement is limited by a stoplug 65 secured to the ladder rail I4. Furthermore, the stop lug 65prevents the jaw part of the coupling member from swinging down too far,when the coupling member is disengaged from the pivot tube 6 and theladder is backed off from the pivot tube 6. Such function of the stoplug 65 prevents the upper part of the jaw 53 from encountering the pivottube 5, as the ladder approaches the pivot tube 6, and assures that thisencountering of the pivot tube will be by the upper part of thedownwardly sloping face portion 531 of the jaw 53 and thus effect theproper upward swinging of the jaw 53 as the ladder more nearlyapproaches the pivot tube 6.

When it is desired to unclamp the ladder from the pivot tube 6, therelease lever 55 is pulled downwardly which causes the coupling memberto be turned with the shaft 5 I, against the action of the spring 58,until the tail piece 54 of the coupling member strikes a lug B4 securedto the pivot tube 6. This amount of pivotal movement of the couplingmember raises the jaw 53 thereof suiiiciently so that the nose 532 ofthe jaw 53 is turned to a position above the pivot bar E. This amount ofmovement ofthe release lever 55 has set up some moment so that continued19 pulling upon the release lever causes the tail piece 54 of thecoupling member to slide on the lug 4 which moves the ladder rearwardlyaway from the pivot tube 6 and thus backs the entire coupling mechanismaway from the pivot tube S.

Certain other structural features of the improved ladder which are shownin the accompanying drawings are as follows:

Adjacently above the upper strut support I I of the upper ladder part 4is pivotally mounted a jointed working platform structure 52 which, whenthe upper ladder section 4 is raised, automatically swings outwardlyfrom said ladder section 4 to provide a support 6I for the workmen, thissupport 6I upon the lowering of the upper ladder section 4 striking therungs of the lower ladder section 3 and folding up with the dependingpart 'I of the platform structure. For obtaining the level of thesupport 6I a longitudinal series of engageable notches are provided inthe depending part of the platform structure. The platform structure 52is made secure in any desired manner before the operator steps on thesupport 5|. In its opening and closing movements the support 6| slidesupon an upper steel rung 2I1 of the upper ladder section 4.

At the top of the upper ladder section 4 a safety belt loop 7l isprovided. Also, insulators 'l2 are provided upon the strut bars 22 forthe lower ladder section 3 and the strut bars 23 for the upper laddersection 4.

What we claim is:

l. For use with a ladder, the sub-combination of a ladder pivot andclamping means comprising, in combination with a support, a pivot barmountable on the support, a clamp pivotally mountable on the ladder andhaving a projecting jaw on one side of its pivotal mounting and a tailpiece upon the opposite side, springs normally holding the jaw inclamping position on the pivot bar, means for unclamping the jaw, a lugon the bar limiting the unclamping movement of the clamp when the jawthereof has been pivotally moved to unclamping position, the tail pieceof the clamp riding on the lugs to push the ladder and the clamp awayfrom the pivot bar upon further movement of the unclamping means.

2. The sub-combination of a ladder pivot and clamping means set forth inclaim 1 in which a ladder guide is provided having flaring opposedsurface portions moving closely adjacent opposed sides of the pivot baras the ladder moves relatively to the bar.

HERMAN J. TROCHE. JAMES HOWARD HOLAN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 219,749 Marshall Sept. 16, 1879 1,899,742 Bay Feb. 28, 19331,952,761 Larsen Mar. 27, 1934 1,953,390 Bosch Apr. 3, 1934 2,035,537Cowan et al Mar. 31, 1936 2,245,481 Kiley et al June 10, 1941

